Switch structure



May 28, 1946. F. 1-:.L WOODy SWITCH STRUCTURE- Filed Sept. 21, 1942 l2 2o Fra-3.2

Insulation 1NvENToR. FREDRIC E. WOOD. BM v V ATTORNEYS I Patented May 28, 1946 SWITCH STRUCTURE Fredric E. Wood, Oak Park, Ill., assignor to Automatic Electric Laboratories, Inc., a corporation of Delaware Application September 21, 1942, SerialNo. 459,121

v claims. (01.200-166) The present invention relates to switch structure and more particularly toixtures for securing operating elements to switch springs. The principal object of the present invention is to provide an 'improved fixture for securing an insulating operating element to a metallic switch spring, which is of simple and rugged construction and which is economicalto manufacture.

Another object of the invention is to provide an improved metallic iixturefor supporting an insulating operating element, which fixture is adapted to be welded to'a thin flexible switch spring in a simple manner without weakening, straining or otherwise injuring the-switch spring. The invention, both as to itsorganization and method of operation, together with further objects and advantages thereof, will best be understood by reference to the followingl specification taken in connection vwith the raccompanying drawing, in which Figure 1 is a plan view ofl an electromagnetic relay incorporating. switch structure embodying thepresent-invention; Fig. 2'is a enlarged sectional view, `taken along the line 4--4 in Fig. 1, of'a portion of Atheswitch structure incorporated inthearelayg- 1.

Referring now more 'particularlyto Figs. 1 to4;

inclusive, of the drawing, the; 'electromagnetic relay there shown comprises amagnetic-core I0 carrying a winding II, a;substantially L-shaped magnetic field element I2 secured to the core III, and a movable magnetic armature I3 pivotally mounted on the outer end of thefleld element I2 and cooperating with the outerv end of the core I0. More particularly;V a nonmagneticshim I2a. formed of bronze or the like is carried on the upper surface of the eld element I2 adjacent the outer end'tliereof, and aIpivot pin I4 is rotatably mounted on the upper surface of the shim I2a by an arrangement comprising la clamping member I5, a washer I6 and a. screw I'I, the pivot pin I4 being arranged in a transverse slot I5a formed in the clamping member I5. 'I'he screw Il extends through aligned holes providedin the washer I6, the clamping member I5 and the shim I2a, and the outer end thereof is received in an aligned tapped hole provided in the iield element I2 adjacent the outer end thereof. Also a downwardly bent tab IBa is formed integrally with thewasher IB and extends through a recess |5b formed in the clampng'member I5 into aligned openings provided in tne shim I2a and the field element I2, thereby positively to prevent relativemotion between the clamping member I5 and the field element I2. Preferably, the

pivot pin I4, the clamping member I5, the washer `I6and the screw I'l are -all formed of non-magnetic material in order-to prevent these elements from interferingv with the magnetic flux path between 4the eld element I2 and the armature I3.

Further the armature. I3 carries a pair of spaced-apart and inwardly directed arms I8 disposed on the oppositesides of the field element- I2 and provided with aligned holes therein which receive the opposite` outer ends of the pivot pin I4, the .opposite outer ends of the pivot pin I4 being iianged over in orderfrigidly to secure the pivot pin I4 to the arms I8`and consequently to the armature I3. Also thev arms I8 are provided `with inturned operating projections I8a which overlie the upper surface of the shim I2a and cooperate with switch structure I9 carried by the field element I2.' More particularly, the switch structure" I9 Acomprises a vplurality of individual flexible metallicswitch or contact springs 20, 2l,

etc., arranged'in two 'stacks and respectively se 'screws "22' and 23.

cured totherfield element I2 by two pairs of More specifically, the base ends of the Asprings 20, 2|, etc., in each stack are spaced apart and insulated from each other l by a plurality of interposed insulating sheets 24 which are retained in clamped position between a clamping plate 25 and the field element I2 by ithe two pairs of screws 22 and23. `For example,

the pair of screws 22 extends through two sets of aligned holes formed in the clamping plate 25, the insulating sheets 24 and the base ends of the contact springs 20, 2I,etc.

Preferably, in each stack, the two adjacent contact springs constituting a cooperating pair, such, for example, as the individual contact springs V2li and 2|, are constructed and arranged in the manner disclosed in U. S. Patent No.

' 2,272,496, Fredric E. Wood; granted February l0,

1942. Accordingly, the contact spring 20 has a substantially Y configuration, the outer free end thereof being splitto provide two diverging arms; while the'contact spring 2I has aclosed ovatelanceolate slot formed therein near its free end in order `to provide diverging and converging arms, the converging arms being connected together at the extreme free end of the switch spring by a curved operating portion 2Ia. Also the two diverging arms of the switch spring 20 carry two metallic contacts'which are arranged in cooperating relationship with two metallic contacts carried by thetwo di'verging arms carried by the contact spring 2 I, the two pairs of cooperating contacts being arranged in crossing relationship as illustrated.

Further a substantially cup-shaped metallic fixture 30 is provided which comprises a nat bottom wall 3I and a substantially cylindrical side wall 32 which converges slightly away from the bottomwalllthe bottom walliil of the fixture 30 being securely fastened tothe* adjacentlower surface of y"the curved operating portion ZIa of the contact spring ZI. Preferably, the bottom wall 3l of the fixture 30 is welded or secured by fused metal to the adjacent lower surface of-.the curved operating portion 2Ia of the contact spring 2I.

This constructionis very advantageous'in view of the fact that tne contact spring 2| is formed of thin flat metallic spring stock; and the fixture 30 is formed by a vsuitable die operation from thin at metallic stock. Hence the fixture 30 lmay be readily welded to the contact "spring 2| .without :.weakening the structure of the contact spring 2 I,

y Finally alsubstantially cylindrical insulating operating "element or bushing 33 isy arranged within the xture 3Bv andl frictionallysecured in place by interlocking vwith the tapered side wall4 32 thereon-"Preferably, one end, of the bushing 33 .-is.provided- .witha frusto-conical section, which is inserted into the cup-shapedlxture 30, and

- 1 then thesidew-all S21-of `the fixture ,30 is spun or pressedd'own into firm engagement with the coni- .cal side wallof`the. received section of the bushing'33.: :Thebushing 33gcooperates directly either with the operating portion, of an adjacent one of the contact springs-.or directly with the inturned operating projection Isacarried by lone oi the` armsl It of1#the: .la1'mat.ure I3.` Preferably, thebushing33 comprises a length which has been out r2-from atrodzyvhichhasfbeen especially prepared.

vvMorefparticularlyfa rod-,is produced by winding into: tight 'spiral form a sheet. or paper, fabric orl thelikewhich has'been impregnated with a'phev nolic on likeresin, and then curing ,under heat 'and pressures: A-bushing comprising a length of s a rod o1 :.the. construction described above is very. l '.:cadvantageousinview of the fact ythat it does not -;have:' any planer-of cleavage.-

the lower end of the bushing 3,3 which engages the operat- .z ing portionzla of the-adjacent. contact spring orV wthexinturnedfoperating, projectionI l8a carried byV .the arm I8I of the amature I3 is suitably rounded f in order .to insure smooth sliding action,

,considering-nomme operation of the relay,

. -whenthewinding II is deenergizedlthe"Contact spring'ZI urges the bushing 33 carried thereby into engagement-with the operating portion of the adjacent contactv spring; While the bushing carriedby the last-mentioned contact spring' engages .theinturnedoperating projection Ilia carried by ,the-arm I8 of the armature i3, whereby the armature I3 and the pivot pin I4 secured theretoV are rotated in the counterclcckwise drection, in 'an obvious manner. More particularly, the pivot pin I4 rotates in the transverse slotl I5a formedin the clamping` member i5, the adjacent upper surface of the shim I2a serving also as'a bearing therefor.' Also, at this time, the

various metallic contacts carried.l by the contact Asprings 20, 2I, etc., are moved into normal circuit positions. When the winding II of the relay is energized the armature I3 is attracted toward the core IU by the magnetic iiux produced in the field structure, whereby the armature I3 and the pivot pin I4 secured thereto are rotated in the clockwise direction, in an obvious manner. This rotation of the armature in the clockwise direction causes the inturned operating projection I8a l carried by the arm I8 to act upon the bushing carried by the associated contact spring and through the operating portion of the contact spring mentioned upon the bushing 33 and consequently upon the contact spring 2l. Accordingly, the contact springs mentioned are flexed, whereby the various metallic contacts carriedby the contact springs 20, 2|, etc., are moved into operated circuit positions.

It is noted that the end of the shim I2a underlying the' projections I8a carried by the arms I8 of the armature I3 prevents the projections mentioned 'from stickingto the adjacent surface of the eld element I2 due to leakage magnetic flux therebetween. The construction of the armature and the means for mounting itl on the field member are claimed in a copending divisional application Serial No. 573,676, led January 20, 1945.

j While oneembodiment of the invention has I been disclosed, it-will be understood that various l scope of the invention. y

What is claimed is: g l. Switch structure comprising a metallic switch spring, a metallic fixture secured by fused metal to said switch spring, and an insulating springs..-

ff '3. vSwitch element frictionally secured to said fixture, said vmodifications may be made therein, and it is intended to cover in the appended claims al1 such i :modifications asffall within the true spirit and f element being adapted to be engaged by a cooperating movable operating member in order to control exing of said switch spring.

2. Switch structure comprising a metallic .switch spring, a metallic cup-shaped fixture havingl azbottom wall secured by fused metal to said switch spring and an outwardly projecting sub- -stantlally cylindrical side wall which converges away from /saidf bottom wall, and a Asubstantially cylindrical insulatingbushing arranged within said fixture and frlctionally secured in place by interlocking engagement with the side wall thereof, an end of said bushing projecting outwardly from 'saidvflxture and.' being adapted to be engaged by a cooperating movable operating member` in. order to controlflexing of said switch structure comprising a -thin flexible metallic. contact.- spring having a free end and a stationary base end; a thin metallic cup-shaped flxture'havingfa bottom wall secured to said contact spring adjacentfthe extreme free end thereof by fused metal' and having an annular side ywall provided with a part of reduced diameter A'spaced `from said bottom wall, and an insulating j secured to said movable portion of said spring and having an annular sidewall projecting therefrom. and a substantially cylindrical non-metalpuhaao lic bushing having a frusta-conical base portion seated within saidcup-shaped fixture, said side wall being spun inwardly into engagement with said frusta-conical base portion to secure said bushing in place, an end of said bushing projects l ing from said vfixture for engagement by a. cooperating movable operating member for the purpose of flexing said spring. t

5.' In a switching device comprising a thin iiat a flexible spring yhaving a movable portion, a metallic cup-shaped fixture having a bottom wall se i cured to said movable portion of said spring. and

having an'annular side wall projecting therefrom, and a substantially cylindrical non-metallic 10 ment by said operating member to permit tilting of the movable portion of saidspring in the event that one part of said spring meets opposition to f movement before another part` does.

FREDRIC E. WOOD. 

